Posts by DimaYasny

Hi All,

I am trying to start writing a wiki-ish CMS I've been contemplating for a while now.

the content will include pics, html content, and should be stored in a database (the current pick is postgres)

A few questions for the more experienced folk 'round here:
1. how do I plan such a database - is there a ready-made data type for a webpage, or do I need to build a table for every component (e.g. pictures). Is there a ready template for such a thing?
2. Python web frameworks - which would be best suited for this? Django is something I'm reading about right now, but there are pylons and turbogears as well
3. The postgres connector - which one is the more popular and the better maintained one? I'm using psycopg right now, but this early in the process, it's easy to switch to another package, if this one is suboptimal.

Any opinions and tips appreciated. I really want to get this project right, so when I open it up, I won't need to blush :)

Thanks,
D.

thanks guys, we've solved it after some extra poking around :)

should have a couple of other questions tomorrow though, if you don't mind

and I'll attach the .ui file next time

Hi guys,

We're writing a GUI based on PyQt, and we're running into an issue when using different resolutions.
Problem is, we can't find how to get the GUI elements to automatically resize when the window is resized, or when the GUI is running on a larger resolution than the one the GUI was originally developed in

I'm using Qt-designer to create the .ui files, if that helps

Thanks nezachem, I do feel that the fuctions aren't exactly set up the best possible way, and I'll add the leading "/" checking as well.

//the girl doesn't want me to give her a one line solution - something like

ls -s myshell /bin/sh

:)

Thanks Nezachem! I have changed quite a lot in the code, and now it does work, with a few exceptions unhandled (like segfaults when getting a permission denied), but those were not mentioned in the assignment anyway.

My main problem was with line 6, where I changed char *com[] to char* com[50], and that started working. I still have no idea why, this being far from my area of expertise, but the girl says she knows why, and that's good enough for me :)

strtok() was a requirement for this assignment, as well as execv(), can't do much about it.

I'm going to dwel on the man pages for wait() now, posting the current working version, in case you have the time to have a look and suggest improvements

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<errno.h>
#define n 50;
#define str [n];
#define str_eq(s1,s2)  (!strcmp ((s1),(s2)))
void get_path(char *);
char *get_line(char *line, int size);


char *get_line(char *line, int size)
{
   if ( fgets(line, size, stdin) )
   {
      char *newline = strchr(line, '\n'); // check for trailing '\n' 
      if ( newline )
      {
         *newline =  '\0'; // overwrite the '\n' with a terminating null 
      }
   }
   return line;
}

void get_path(char cmd[50])
{
    char command[50] = {0} ; //full command with path included
    char *tempcmd = NULL;
    char *commandptr = NULL;
    char *result = NULL; //path iterator
	char* com[50]; //command with args, no path
	char *arg = NULL; //list of arguments, path and command excluded
	char delims[] = ":"; //path iteration delimiter
	char delims1[] = " "; //
	char * path; //variable to hold the full path delimited by ':'
	int status; //process flow control
	int argcount = 0; //argumetn counter, where 0 is the command
    int pid;   
    char *cmd1; //just the command, no args or path
   
    tempcmd=cmd; //assign to temp variable, so strtok doesn't ruin cmd
    path=getenv("PATH");
    if (path != NULL)
        printf("%s \n", path);
    else exit(1);    
	
    arg = strtok( tempcmd, delims1 ); 
    com[0] = arg; //place the command into com[0]
    cmd1=arg;
    while( arg )
    {
	  argcount++;
	  arg = strtok(NULL,delims1);
	  com[argcount] = arg;
	}
	argcount++;
	com[argcount]=NULL; //last value in args should be NULL
    
    result = strtok( path, delims ); 
    while( result ) 
    {
       strcpy(command, "");
       strcat(command, result);
       strcat(command, "/");
       strcat(command,cmd1);
       commandptr=command;
    
       if (( pid = fork()) == 0 ) 
        {
            printf("Executing Command: %s \t ", command);
            execv(commandptr, com);
            if (! strerror(errno) == "No such file or directory")
            {
                printf("\n\t %s\n", strerror(errno)); //print Error 
                exit(1);    
            }    
            
        }
        else 
		{
           wait(&status);
           printf("2"); 
           if (status != 0)
                printf ("3");

        }   
        printf("\n------------------------------\n");
        result = strtok( NULL, delims ); 
    } 
}

void main()
{
	char cmd[50];
	char leave[]="leave";

  	while (!str_eq(cmd,leave))
  	{
		printf("Enter command: ");
        get_line(cmd, sizeof cmd);   
		if (!str_eq(cmd,leave))  
			get_path(cmd);
  	}
	
    printf("bye\n");
}

Thanks, but the article uses execve, which is not an option for me in this case.

I was just looking for an explanation for line 46, 52 and 54 in my code

Hi all,

I'm helping my girl out with her hw, (/me not knowing C at all, but someone has to help, right?)
I am supposed to read user input, and then try to execute a given command plus the arguments in every given $PATH.

I managed it all, but I get puzzled by the execv function, which I am supposed to be using, it doesn't produce any stdio, and I can't seem to find a way to make it work

a basic command

execv ("/bin/touch", "/tmp/test123", NULL);

doesn't do anything, neither do I see an exit code.
How do I use it?

Here's what I've got so far:

void get_path_exec(char cmd[50])
{
    char command[50] = {0} ; //full command with path included
    char *tempcmd = NULL;
    char *result = NULL; //path iterator
    char *com[] = {0}; //command with args, no path
    char *arg = NULL; //list of arguments, path and command excluded
    char delims[] = ":"; //path iteration delimiter
    char delims1[] = " "; //
    char * path; //variable to hold the full path delimited by ':'
    int pid, status; //process flow control
    int argcount = 0; //argumetn counter, where 0 is the command
   
    tempcmd=cmd; //assign to temp variable, so strtok doesn't ruin cmd
    path=getenv("PATH");
    if (path != NULL)
        printf("Path is %s \n", path);
    else exit(1);    
	
    arg = strtok( tempcmd, delims1 ); 
    com[0] = arg; //place the command into com[0]
    while( arg )
    {
	  argcount++;
	  arg = strtok(NULL,delims1);
	  com[argcount] = arg;
	  printf("arg is %s \n", arg);
	}
	argcount++;
	com[argcount]=NULL; //last value in args should be NULL, right?

    result = strtok( path, delims ); 
    while( result ) 
    {
       strcpy(command, "");
       strcat(command, result);
       strcat(command, "/");
       strcat(command,cmd);
       strcat(command,"\0"); //gather all parts of full path'd command - path, "/" and cmdname
//       printf("full command: %s \n\n", command);
       
       if (( pid = fork()) == 0 ) //create a new process
        {
            execv(command, com);
//below is a point I don't get
            printf("Something happened here, but what? %s \n Status is %d \n\n", result, status);
            exit(1);
        }
        else 
		{
           wait(&status);
           printf("Something else happened here %s \n Status after wait is %d", command, status);
           if (status != 0)
                printf("And something happened again? \n");
        }   
        result = strtok( NULL, delims );
    } 
}

The entire pid-fork-&status structure is just too vague for me, can anyone explain what happens on every step of the way?

Using execl, by the way, worked for me, but I have to use execv.

Thanks